This disclosure relates to wireless communications.
Wireless communication devices can use positioning signals, such as those obtained from global positioning system (GPS) satellites orbiting the earth, to determine a location estimate. Determining a location estimate can include estimating a current location of a device, estimating a velocity of a device, or both. The location estimate can be communicated within a wireless communication system to provide one or more location based services.
The devices can use one or more wireless communication technologies, such as orthogonal frequency division multiplexing (OFDM) and Code Division Multiple Access (CDMA), to communicate. In an OFDM based wireless communication system, a data stream is split into multiple data substreams. Such data substreams are sent over different OFDM subcarriers, which can be referred to as tones or frequency tones. Wireless communication devices can communicate based on one or more wireless technologies such as Long Term Evolution (LTE), Universal Mobile Telecommunications System (UMTS), Global System for Mobile Communication (GSM) protocols, systems based on CDMA such as CDMA2000 and Wideband CDMA (WCDMA), and Worldwide Interoperability for Microwave Access (WiMAX). Various examples of wireless communication devices include mobile phones, smart phones, wireless routers, wireless hubs, base stations, and access points. In some cases, wireless communication electronics are integrated with data processing equipment such as laptops, personal digital assistants, and computers.
In some wireless communications systems, a wireless communication device can use discontinuous reception (DRX) method in idle mode to reduce power consumption. By using DRX, the wireless communication device can turn on its receiver only during a pre-scheduled cyclic paging interval and turn off its receiver to enter a low power state during other times. In order to “wake up” the wireless communication device, a paging message can be sent from a network component (e.g., a base station) at a specific timeslot within the pre-scheduled paging interval. By decoding the paging message, the wireless communication device can estimate an arrival time of its data and establish or resume a connection by sending a connection request message.